The long-term objective of this application is to understand the neural mechanisms of language comprehension in real-world settings, and how the brain makes use of context to aid in communication. The overarching hypothesis is that there is no fixed part of the brain for processing speech;rather, communicative context determines the organization of the brain's response to language. Aim 1 uses naturalistic stimuli to explore how functional organization changes over development as a result of changes in the relative salience of particular stimulus dimensions. Aims 2 and 3 use a combination of naturalistic and controlled stimuli to explore moment-to-moment changes in this organization in response to communicative context established by co-speech gestures (Aim 2) and discourse (Aim 3). The training goals for the mentored phase are the development of advanced techniques for the analysis and interpretation of neuroimaging (fMRI and EEG) studies approximating real-world communication, the acquisition of new techniques, and training in developmental cognitive neuroscience. These will be extended into the independent phase, laying the foundation for a broader, generative program of research and establishing an independent career path investigating how the brain makes use of these and other forms of context in real-world settings throughout the lifespan. RELEVANCE: This research has the potential for broad impact because it addresses how networks of brain areas interact under conditions that approximate real-world communication. As such, it introduces novel methods to the study of the neurobiology of speech perception that will have translational benefits for studies involving developmental and patient populations that may have difficulty participating in more controlled studies.